Gentleman,
I am in need of experience and expertise...
Can someone tell what might have gone wrong here? Or hypothesize such that I can try to figure out what is going on?

As always, I am deeply indebted and humbled by the knowledge of those in the profession.

Injector Seal Ring Burn through Picture

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique